Place track and in the end of that track place a turntable

Place a crosstrack (start on only one end of the truntable) and rotate the turntable to place another one and try eye ball a triangle like in the image, repeat this step for as many engine sheds you want/can fit

Place 14 meter bridge (or any track type) section in the end of the crosstrack and then place 21-22 meter section of bridge in the end of the 14 meter bridge as seen in the second image and repeat until every crosstrack is done

Delete the 14 metre bridge sections

Use the mouse and WASD keys to align the engine shed to the end board on the bridge eye ball it to be close enough and then with out moveing the mouse use W and S key to move back and forward to see if the parts on the shed appear and disappear about the same time on both sides of the shed

UE5 beta (rotating buildings update)
face the bridge section as square as you can, line up the lower edge of the screen to the bridge or something then select the engine shed you want to use, if needed rotate it the right position

With out moving the mouse use W and S keys to get the right height of engine shed, the bottom of the engine shed track should be either a bit lower or higher then the front board of the 21-22 metre bridge section, look at the image

UE5 (rotating buildings update) same but don't need to worry about the mouse movement

Use the front board of the bridge to align ground works, then eye ball the ground work to the corner of the shed and place it, result in the last image, later use same method to do the other engine shed in the front. The sides and back you can do as you are finished with other parts roundhouse

Rotate roundtable like its in image 1 and place the first track, then look at image 2 and see how to place the second track, repeat for other sheds

Aim about where im aiming and delete crosstracks and anything else what is not needed anymore